In a remarkable celestial discovery, astronomers utilizing the Karl G. Jansky Very Large Array (VLA) have identified a millisecond pulsar within the globular cluster GLIMPSE-C01, marking a significant milestone as the first pulsar ever detected in this particular cluster. The breakthrough emerged as part of the VLA Low-band Ionosphere and Transient Experiment (VLITE), and the findings were recently detailed in a paper on the arXiv pre-print server dated December 18.
Pulsars, captivating astronomical phenomena, are highly magnetized neutron stars that exhibit rapid rotation, emitting electromagnetic radiation in the form of radio waves from their poles. Millisecond pulsars (MSPs), characterized by rotation periods below 30 milliseconds, are believed to originate in binary systems, with the initial massive component transforming into a neutron star subsequently spun up through accretion from a companion star.
Recognizing the potential for MSP formation in globular clusters (GCs) due to their elevated stellar densities, a team led by Amaris V. McCarver from Texas Tech University embarked on a comprehensive search for pulsars in nearly a hundred GCs. Leveraging radio imaging from VLITE and the VLITE Commensal Sky Survey (VCSS), the researchers identified ten promising sources from the sample of 97 globular clusters.
Among these, GLIMPSE-C01 emerged as the standout candidate—a dense, massive intermediate-age GC situated approximately 10,760 light years away from Earth. Designated GLIMPSE-C01A, the newfound pulsar boasts a spin period of 19.78 milliseconds and a dispersion measure of 491.1 pc/cm³. Notably, this pulsar exhibits an unusually steep spectrum, and additional analysis involving radio, X-ray, and infrared data confirmed its pulsar nature.
What distinguishes GLIMPSE-C01A is its higher hard X-ray luminosity (2–10 keV) compared to most MSPs in globular clusters, coupled with a slower spin period. This hints at a formidable magnetic field, estimated at an astonishing 1 billion Gauss, with a characteristic age pegged at around 100 million years.
The researchers underscore the importance of regular timing observations and the establishment of an orbital and timing solution for GLIMPSE-C01A to unveil more intricacies about this pulsar. Their discovery not only sheds light on the unique properties of this celestial object but also highlights the efficacy of spectral index searches as a valuable tool in pulsar exploration.